Energy absorbing device

ABSTRACT

An energy absorbing device comprising: an energy absorber, including relatively fixed and telescoping portions; a lever operatively connected to said energy absorber; a wheel, including a pressurized tire rotatably carried on said lever; pressure sensors carried on said wheel for monitoring the pressure in said tire; and means for modifying the energy absorbing characteristics of said energy absorber means in response to signals transmitted from said pressure sensors to minimize the effect of vertical deflections on said energy absorber.

United States Patent Palmer et al.

[451 Apr. 4, 1972 [54] ENERGY ABSORBING DEVICE [72] Inventors: Roy M.Palmer, South Bend, lnd.; Robert J. Schoenhals, Tempe, Ariz.

[73] Assignee: The Bendix Corporation [22] Filed: May 8, 1970 [21] Appl.No.: 35,721

[52] US. Cl. ..244/l03 R, 188/299, 280/124 F [51 Int. Cl. ..B64c 25/58[58] Field of Search ..244/l03, 104, 102, 100, 103 R; 152/333, 415, 416,417; 280/124 F, DIG. 1; 188/299 [56] References Cited UNITED STATESPATENTS 2,810,535 10/1957 Albright ..244/104 3,035,853 5/1962 Klein....280/l24 F 3,124,368 3/1964 Corley et a1... ...280/D1G. 1 3,528,6799/1970 Gant ....152/416 X FOREIGN PATENTS OR APPLICATIONS 940,656 5/1948France ..152/333 1,273,336 7/1968 Germany ..244/104 PrimaryExaminerMilton Buchler Assistant Examiner-Paul E. SaubererAttorney-Gordon H. Chenez and Plante, Arens, Hartz, Smith and Thompson[5 7] ABSTRACT An energy absorbing device comprising: an energyabsorber, including relatively fixed and telescoping portions; a leveroperatively connected to said energy absorber; a wheel, including apressurized tire rotatably carried on said lever; pressure sensorscarried on said wheel for monitoring the pressure in said tire; andmeans for modifying the energy absorbing characteristics of said energyabsorber means in response to signals transmitted from said pressuresensors to minimize the effect of vertical deflections on said energyabsorber.

7 Claims, 2 Drawing Figures PATENTEDAPR 4 I972 INVENTORS ROY M. PALMERBY ROBE/P7 a SCI-IOE/VA/ALS AGE/VT BACKGROUND OF THE INVENTION Thisinvention relates to an energy absorbing device for use with an aircraftlanding gear, and more particularly, to a gear for landing on roughterrain. Theoretical and experimental studies of the problem of landingand taxiing over rough terrain have shown that the conventional shockabsorbing mechanisms known in the art are incapable of satisfactorilyattenuating loads resulting from bump impact vertical deflections. Thisis primarily due to the fact that the shock absorbing mechanism is notcompatible with the frequencies and mode shapes of the bump impactinput. As a result, the shock strut usually acts essentially as a rigidlink, stroking only a small amount, where most of the loads are absorbedby the tire and/or transmitted directly to the airframe through thelanding gear hard points.

SUMMARY OF THE INVENTION It is an object of this invention to provide animproved-energy absorbing device for use in connection with landing onrough terrain.

It is an object of this invention to provide an improved energyabsorbing device that is not impaired during its use on normal landingterrain.

It is an object of this invention to provide an improved energyabsorbing device that is adaptableto any conventional type of landinggear system.

It is an object of this invention to provide an energy absorbing devicehaving a pressure device which is sensitive to variations in tirepressure and which upon bump impact will control a valve which in turnwill modify the energy absorbing characteristics of the energy absorbingdevice.

Other objects and features of the invention will be apparent from theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view,partially in section, showing a landinggear arrangement whichincorporates the invention;

FIG. 2 is a sectional view of the wheel showing the air chambersinternal to the tire.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, it will beseen that the energy absorbing device, which is indicated generallyby-the numeral '10, is comprised of an energy absorber 12, a lever 14, awheel 16, pressure sensing means indicated generally by the numeral 18and suitable means 20, such as a valve, for modifying the energyabsorbing characteristics of the energy absorber 12. The energy absorber12 is a conventional shock absorber or strut which includes an upperportion 22 and a lowertelescoping portion 24. The upper portion 22 isrigidly secured to the frame of the aircraft 26, only a fragmentedportion of which is shown. The lever 14 is pivotally connected at 28 toan extended portion 30 of the upper portion 22 of the energy absorber12. The wheel 16 is rotatably carried at 32 by the lever 14. The wheel16 is comprised of a rim 34 and a tire 36. The tire 36 is separated intoa plurality of independent air tight compartments 38, as shown in FIG.2.

The pressure sensing means 18 is comprised of a plurality of sensormembers 40, a-receiver 42 and a conduit 44. The sensor members 40 aremounted so as to project into the interior of each of the compartments38. Each sensor member 40 in-.

cludes a portion which is sensitive to pressure changesin its respectivecompartment, and a suitable battery powered electronic transmitter whichhas an output signal amplitude directly responsive to the pressuresensitive portion, which in turn is directly responsive to the pressure(or pressure change) in the compartment 38 of the tire 36. Reference ismade to pressure transducer type 4-356 manufactured by CEC/TransducerDivision, Bell and Howell Co. for an example of one device substantiallyequivalent to sensor member 40. The

I receiver 42 is non-rotatably carried on the lever 14 in closeproximity to the sensor members 40. The receiver 42 is simul taneouslyresponsive to all of the sensor members 40 and will have anoutput-control signal whose amplitude is equal to the highest amplitudeof any of the sensor members 40. Reference is made to Peak DetectorModel SA32 6 manufactured by the Bell and Howell Co. for an example of acommercially available device similar to receiver means 42. The receivermeans 42 includes a conduit 44 which communicates the output control'signal of the receiver 42 to the valve 20 for control thereof. I

, The valve 20 has a suitable variable orifice (not shown) forregulating fluid 'flow from chamber 46 to chamber 48 in response to thecontrol. signal from the pressuresensing means 18. With such anarrangement it is possible for the energy ab- MODE OF OPERATION OF THEPREFERRED EMBODIMENT With the foregoing structural description it willbe evident to those skilled in the art that the invention resides insensing tire compartment pressure changes which occur upon impact with arock, or bump 50, or a hole or rut 52 and utilizingthis sensed pressurechange to modify the normal damping characteristics of the energyabsorber. 12 and thereby minimize, if not eliminate, the effect ofvertical deflections on the airframe 26.

Assume then that a landing is being made on rough terrain by an aircraftequipped with the energy absorbing devicev 10. Upon touch-down of thewheel 16 on the generally level portion of the terrain 54', the energyabsorbing device l0 would typically be loaded, as shown in FIG. 1. Uponengagement of the tire 36 with the rock 50, as shown in FIG. 2, theairpressure in compartment 38 increases sharply. The sensor member 40detects this pressure increase and transmits a signal via the 1 receiver42 and conduit 44 to. the valve 20 whereby a change is made in theorifice setting of the valve 20' to allow a rapid stroking of theprimary energy absorber 12, as the wheel 16 passes over the rock 50.

While specific details have been herein shown and described, theinvention is not confined thereto since other changes and substitutionscan be made within the spirit and scope of the invention.

We claim:

1. An energy absorbing device comprising:

energy absorbing means, including relatively fixed and telescopingportions;

lever means operatively connected to said energy absorbing means wheelmeans including a pneumatic tire rotatably mounted on said lever means;-

pressure sensing means carried on said wheel means for monitoring thepressure in said tire; and

means for modifying the energy absorbing characteristics of said energyabsorber means in response to signals transmitted from said pressuresensing means to minimize the efiect of vertical deflections on saidenergy absorber means as said wheel means is subjected to relativelylarge vertical deflections.

' 2. An energy absorbing device, as recited in claim 1, wherein saidmeans for modifying the energy absorbing characteristics of said energyabsorber means is a valve means.

3. An energy absorbing device, as recited in claim 2, wherein said valvemeans is responsive to electrical control signals.

4. An energy absorbing device, as recited in claim 3, wherein saidpneumatic tire includes a plurality of compartments.

5. An energy absorbing device, as recited in claim 4, wherein saidpressure sensing means comprises:

a sensor member projecting interiorly of at least one of saidcompartments to sense a change in compartment pressure in response to abump impact vertical deflection;

said sensor member converting said pressure change to a control signal;and

receiver means non-rotatably carried by said lever means in closeproximity to said sensor member for receiving said control signal;

said receiver means including a conduit means for communicating saidcontrol signal to said valve means for control of said valve means.

6. An energy absorbing device, as claimed in claim 1,

wherein:

said lever means is pivotally mounted at one end to said fixed portion;

said wheel means is rotatably mounted on the opposite end of said levermeans and adapted to cause pivotal movement of said lever means.

7. An energy absorbing device, as claimed in claim 1,

5 wherein:

said fixed portion defines a fluid filled first chamber;

said telescoping portion defines a second chamber having an orificeproviding fluid communication with said first chamber and through whichfluid is transferred from said l0 first chamber to said second chamberin response to telescoping movement thereof; said means for modifyingthe energy absorbing characteristics of said energy absorbing meansincluding valve means operatively connected to said orifice for varyingthe effective flow area thereof and means responsive to deformation ofsaid tire resulting from bump impact therewith operatively connected tosaid valve means for actuating the same.

1. An energy absorbing device comprising: energy absorbing means,including relatively fixed and telescoping portions; lever meansoperatively connected to said energy absorbing means wheel meansincluding a pnEumatic tire rotatably mounted on said lever means;pressure sensing means carried on said wheel means for monitoring thepressure in said tire; and means for modifying the energy absorbingcharacteristics of said energy absorber means in response to signalstransmitted from said pressure sensing means to minimize the effect ofvertical deflections on said energy absorber means as said wheel meansis subjected to relatively large vertical deflections.
 2. An energyabsorbing device, as recited in claim 1, wherein said means formodifying the energy absorbing characteristics of said energy absorbermeans is a valve means.
 3. An energy absorbing device, as recited inclaim 2, wherein said valve means is responsive to electrical controlsignals.
 4. An energy absorbing device, as recited in claim 3, whereinsaid pneumatic tire includes a plurality of compartments.
 5. An energyabsorbing device, as recited in claim 4, wherein said pressure sensingmeans comprises: a sensor member projecting interiorly of at least oneof said compartments to sense a change in compartment pressure inresponse to a bump impact vertical deflection; said sensor memberconverting said pressure change to a control signal; and receiver meansnon-rotatably carried by said lever means in close proximity to saidsensor member for receiving said control signal; said receiver meansincluding a conduit means for communicating said control signal to saidvalve means for control of said valve means.
 6. An energy absorbingdevice, as claimed in claim 1, wherein: said lever means is pivotallymounted at one end to said fixed portion; said wheel means is rotatablymounted on the opposite end of said lever means and adapted to causepivotal movement of said lever means.
 7. An energy absorbing device, asclaimed in claim 1, wherein: said fixed portion defines a fluid filledfirst chamber; said telescoping portion defines a second chamber havingan orifice providing fluid communication with said first chamber andthrough which fluid is transferred from said first chamber to saidsecond chamber in response to telescoping movement thereof; said meansfor modifying the energy absorbing characteristics of said energyabsorbing means including valve means operatively connected to saidorifice for varying the effective flow area thereof and means responsiveto deformation of said tire resulting from bump impact therewithoperatively connected to said valve means for actuating the same.